The study's senior author, David Feldman, MD, professor of medicine, who has been studying vitamin D for 25 years, had shown in previous studies that a form of the vitamin, known as calcitriol, limits the growth of prostate cancer cells. Calcitriol, the active form of vitamin D, is the metabolite that is created in the body after consumption of vitamin D-containing food or exposure to the sun.
Feldman wanted to see if he could boost calcitriol's effects and lower the dose by using it in conjunction with another drug. He and his colleagues, including professor of urology Donna Peehl, PhD, who specializes in developing models of prostate cancer in cultured cells, found that by using calcitriol with nonsteroidal anti-inflammatory drugs, or NSAIDs, they could suppresses prostate cancer growth in vitro even more-and with smaller doses-than using either drug alone.
"There is great enhancement when the drugs are given together, using what we think is a safe dose in humans," said Feldman. "It's hard to make an exact comparison, as we are talking about cells in a dish and not a person." Still, based on the findings, he and his colleagues have already begun a clinical trial in men who have a post-treatment recurrence of prostate cancer. Both calcitriol and nonselective NSAIDs have been used in humans for years, and the safety and risks of these drugs are well known.
According to the Centers for Disease Control and Prevention, nearly 30,000 men die annually in the United States from prostate cancer. Among cancers,
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Contact: Mitzi Baker
mabaker@stanford.edu
650-725-2106
Stanford University Medical Center
1-Sep-2005